scholarly journals Processing, Mechanical Properties and Morphology of Styrene-Butadiene Block Copolymer.

1991 ◽  
Vol 48 (10) ◽  
pp. 649-656
Author(s):  
Ikuro YAMAOKA ◽  
Masao KIMURA
Keyword(s):  
Mechanical Properties ◽  
Block Copolymer ◽  
Styrene Butadiene

scholarly journals Influence of Controlled Epoxidation of an Asymmetric Styrene/Butadiene Star Block Copolymer on Structural and Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 96
Author(s):  
Shankar P. Khatiwada ◽  
Ulrike Staudinger ◽  
Dieter Jehnichen ◽  
Gert Heinrich ◽  
Rameshwar Adhikari
Keyword(s):  
Mechanical Properties ◽  
Block Copolymer ◽  
Chemical Modification ◽  
Tensile Modulus ◽  
Elongation At Break ◽  
Cylindrical Structures ◽  
Star Block Copolymer ◽  
Higher Temperature ◽  
Styrene Butadiene ◽  
Clear Increase

The chemical modification (namely the epoxidation) of a star shaped block copolymer (BCP) based on polystyrene (PS) and polybutadiene (PB) and its effect on structural and mechanical properties of the polymer were investigated. Epoxidation degrees of 37 mol%, 58 mol%, and 82 mol% were achieved by the reaction of the copolymer with meta-chloroperoxy benzoic acid (m-CPBA) under controlled conditions. The BCP structure was found to change from lamellae-like to mixed-type morphologies for intermediate epoxidation level while leading to quite ordered cylindrical structures for the higher level of chemical modification. As a consequence, the glass transition temperature (Tg) of the soft PB component of the BCP shifted towards significantly higher temperature. A clear increase in tensile modulus and tensile strength with a moderate decrease in elongation at break was observed. The epoxidized BCPs are suitable as reactive templates for the fabrication of nanostructured thermosetting resins.

scholarly journals Influence of Ultraviolet Radiation on Mechanical Properties of a Photoinitiator Compounded High Vinyl Styrene–Butadiene–Styrene Block Copolymer

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1287
Author(s):  
Sanjoy Datta ◽  
Radek Stocek ◽  
Kinsuk Naskar
Keyword(s):  
Mechanical Properties ◽  
Block Copolymer ◽  
Ultraviolet Radiation ◽  
Thermoplastic Elastomer ◽  
Labile Hydrogen ◽  
Hydrogen Atoms ◽  
Time Saving ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

Ultraviolet curing of elastomers is a special curing technique that has gained importance over the conventional chemical crosslinking method, because the former process is faster, and thus, time-saving. Usually, a suitable photoinitiator is required to initiate the process. Ultraviolet radiation of required frequency and intensity excites the photoinitiator which abstracts labile hydrogen atoms from the polymer with the generation of free radicals. These radicals result in crosslinking of elastomers via radical–radical coupling. In the process, some photodegradation may also take place. In the present work, a high vinyl (~50%) styrene–butadiene–styrene (SBS) block copolymer which is a thermoplastic elastomer was used as the base polymer. An attempt was made to see the effect of ultraviolet radiation on the mechanical properties of the block copolymer. The process variables were time of exposure and photoinitiator concentration. Mechanical properties like tensile strength, elongation at break, modulus at different elongations and hardness of the irradiated samples were studied and compared with those of unirradiated ones. In this S-B-S block copolymer, a relatively low exposure time and low photoinitiator concentration were effective in obtaining optimized mechanical properties. Infrared spectroscopy, contact angle and scanning electron microscopy were used to characterize the results obtained from mechanical measurements.

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